Baffle assembly for air circulators



Oct. 5, 1943. E. o. WEHMEYER 2,331,063

BAFFLE ASSEMBLY FOR AIR CIRCULATORS Filed Sept. 26, 1941 INVENTOR.EDWARD O. WEHMEYER Patented Oct. 5, 1943 2,331,063 3mm ASSEMBLY ro-Ram-cmfimmh w gd 0," Wehmeyer, St-LQ l SlLM Application September 26,1941,. swam. 412ml Ihis invention relates to'im-provements'in baffieassemblies forair circulators, the elements of novelty and features ofdesign being particularly but not solely applicable as, embodiment insmall portable orsemi-{portable room-air circulator units.

There are prevalently widely sold, s ubstant ial numbers of aircirculator-uni-ts of the types char acterized by apropellerfanoperatively connected to a vertical shaft'moton wi'th a'generallyconeshaped bafile disposed across tlie dischargestream of the fan.Such bafiles are employed with the general object of deflecting the air;dischargedby the fan, in a'hori'zontal and partly downward directionthroughout a given zone. of the roorri or other space in which thecirculatoris utilized;

It has been discovered; asa resulto f exhaustive tests with variousmeans for determining direction and velocity of air movement, that theconventional baflies employed in units of the ,type noted, arerelatively inefiicient,and fail ingreat measure in their intendedfunctionbecause of the fact that the air deflected b the conventionalbefits is so di t ed tha l rge prona t o thereof abruptly engages theiloor or similar :hOri

zontal surface in azone not far outwardly of the unit. This results in afrebound eifect and'is undesirable since suchefiectimpairs'theeifectivecoverage orarea of spreadofthe airstream: "The w d ve o uQh treamWi hWei e tiona]. bailles is thus considerablyimpaired byuna wantedturbulence, the tendencyto drive ,dustor other foreign particles fromthe floor up ,into t he m, an y rb n lr,,.gpe e es t d tr from themaximum cooling-efiect' ,of the unit which would be obtained but'iorthenoted shortcoming. It is accordingly a majorobjectof the invention toimprove .the direction or trend of air stream discharged from unitsofthe notedtype;

fies, thus minimizing height and in many cases weight and spacerequirements in generahof air ciroulator units.

Yetanother object of the invention is attained in an improved means forvarying at-willpasby manual adjustment, the angle of' 'deflection ofth'eannular air streamemittediby circulator units of typesemploying-abaflle-w-ith a'propeller type fan or the like, such facilities forangular waria-f tion of the air discharge stream,enabling this.adjustment without interierence with the full advantages meted in thepreceding objects. 1

Further objects, somewhat ancillary to athose heretofore noted, may be(stated as iattained in a greater spread or wider distribution, of theair impelled outwardly -of-a tan and baffietype circulator; theelimination, of I resonance effects sometimes heretofore experienced,panticularly with metal baflles ior the general purpose noted and theprovision of improved -means for adjusting a bafile elemen-t .ora partof the baflle :assem i tion with the accompanying drawing, =in w-hich;Fig.1-is a side elevation, somewhat reduced-in proportion, of a portableroom air circulating uni-t to which the present improvements arefapplied; I Fig. 2 is a vertical sectionalelevation"of-:the

motor, fan, a portion of a. housing thereabout'," and a bafile,particularly showing the rela'tion'of the fan tothe bafiie;

Fig. 3 is a vertical sectionalelevation era somewhat modified ba'flle'structure;

' Fig. 4 is a vertical sectionalgelevation of a rurther modified form of*bafiie with which isi provided means for adjusting certain of theelements of the battle structure in order tovar-y the angle; v

of air delivery from the baffle; I

Fig. 5 is a fragmentary sectional elevation showing certain fth'e partsofF-i-g. 4 ina dinerent adjusted position, and

Fig fi is an enlarged section; in a-verticaLplane,

of a marginal portion of the baffle -shownin'-= Fig.

2, in order bettertoillustrate the sectional curva ture of a marginalportion of the'bafile, and the function of such portion indefiectingpants'cf the air stream.

Proceeding nowto a description of partsliby characters of reference tothe drawing, it will benoted that one of thefmany advantageous em---bodiments' of-the present improvements is in a small portableunit -forcirculating air in a room F or other enclosure, and-in which unit apropellertype' fan is employed, rotatiVely mountedon lthe V shaft-of avertically disposed motor, with axbaflle.

or the like adjacent and above theefama In such a unit the discharge ofair is effected peripherally of the unit in the regions of the margin ofthe baflie, and the annular discharge stream emanating from the baflieis projected horizontally in part, yet given a somewhat upward oroptionally a downward trend.

The small unit selected to exemplify an installation of the kind notedincludes a pair or more of vertical frame members 10, each of generallyrectangular form, formed of a tubular stock, and provided with asomewhat widened floor engaging portion ll. One side of the unit onlybeing shown, there appears in Fig. 1 only a single such structure lil-lI. In this unit, a fan actuating motor l2 is carried by a transverseportion [3 of a somewhat cylindrically shaped enclosure M. The latter isprovided with a patterned arrangement of air-inlet openings, forexample, such as shown at I5. The structure l4 thus serves, through theelement l3, to carry the motor l2, the latter being fixed in position inthe element [3 as by screws or the like [6. The housing element I4 is,in turn, so arranged that it derives its primary support from theVertical elements 20, being theriser members at each side of thesupporting frame If), screws 2| serving to position the housing I l tothe members 20.

Supported close to, and yet just above the housing 14, is a bafilestructure indicated generally at 22. certain of the parts in section andsomewhat enlarged, the baffle structure 22 is of a diameter, in case itbe of circular form, somewhat approximating the diameter or greatestcross dimension of the housing l4. Located just within and below theupper margin of the housing I4 is a multiblade propeller type fan which,may be of any suitable or conventional form, and is indicated generallyat 23. The fan is provided with a hub structure 24 secured as by asetscrew 25 to the motor shaft 28. A convenient and simple means formounting the baflle structure 22 in assembly, consists of screws 3!] oneof which extends at an appropriate height, through each of the riserelements 20 of the side frames, and into engagement with the bafflestructure.

Proceeding now to a description of the novel features of the bafflestructure such as 22, the latter is shown in Fig. 2 as consisting of asingle piece of wood, plastic material or other non-metallic andnon-resonant substance. If constructed of wood, or even of a syntheticplastic, the element 22 may be and preferably is formed of a pluralityof laminations (not shown) adhesively secured together and compacted asby hydraulic pressure into what is in effect a single block or unit. Thebaffle forming block is preferably thus integrated, unless formed of asingle piece of wood for example, prior to contouring.

The contouring or shaping of the baffle particularly the surface thereofconfronting the fan and constituting the major or primary baiilesurface, as well as the perimeter or marginal portion bounding suchsurface, go to the essence of th present invention. The prevailingpractice has heretofore been to construct, for economy, baflle elementsfor this general purpose, of sheet metal pressed to a frusto-conical orsimilar shape. Such baflles are prevalently of such form as to present apartly conical surface as the major baflling area, and are furthercharacterized by the usual sharply angulate periphery or corner. Bothformerly prevailing practices make for an adverse and. unwanted airdeflecting effect, namely, the tendency of the annular streams de- Aswill be seen from Fig. 2, showing fiected outwardly of the baffle, toproceed along no uniform outward course, but generally within a zone siXto eight feet outwardly of the unit to strike the floor or other supportfor the unit and rebound therefrom. It has been found by an exhaustiveseries of carefully conducted experiments, that this effect can beentirely eliminated by convexly curving, on a substantial radius, thesurface of the baffle which is first or primarily engaged by thedischarge stream of the fan. The adverse effect above noted is furtherobviated and the spread of the air stream delivered beyond the bafile isstill further enhanced, by avoiding any semblance of a sharp ordistinctly angulate corner at the margin of the primary bafflingsurface, specifically by providing a rounded margin or edge of thebaflle in this zone. The convexity of the margin is, however, due to asectionally arcuate shaping on very much smaller radii than is thesurface of the primary baflling area.

It will be obvious that the exact radii-of curvature to be given, first,the primary baflle surface, and secondly, the baffle margin, will dependsomewhat on the diameter of fan, hence the diameter of the unit withwhich the baffle is employed.

The experiments conducted clearly indicate, however, that the curvaturesnoted in improvement of the pattern of delivered air stream are criticalwithin limits to produce the desired effects. For example, an optimumrelation of radius of sectional curvature of the primary bafflingsurface to the diameter of the fan, has been found to lie between limitsof one and one-half to three times the diameter of the fan, best resultshaving been obtained when this ratio is slightly greater than 2:1. Toprovide a specific example, with a 12" propeller and a baflle elementsuch as 22 only slightly larger in diameter than the propeller, a radiusof twenty-five and one-half inches such as indicated by line 32 drawn oncenter 33, will produce the most favorable results.

Further in reference to the example selected for illustration, it hasbeen found that the radius of sectional curvature of the margin 34, whenemployed in a bafile approximating the diameter of a 12" fan, suchradius of curvature, taken say on line 35, produces the best resultswhen it is of the order of five-eighths inch, and with fans of ordinaryand usual diameters, a lower limit of slightly less than one-half inch,and an upper limit of one inch for this radius are regarded aspractical.

It has been found after repeated experimental trials, that the unusuallyshallow construction of baffle characterizing the present improvementsserves not only to produce an improved pattern of the annular air streamdelivered from the unit, but effects a substantial reduction in thenecessary vertical dimension or headroom requirement of the functionalportions of the assembly. This feature makes for a smaller, more compactunit than would be required according to heretofore prevailing theoriesof design.

It is important to note that while the baflle structure 22 is shown asbeing of appreciable depth, such proportioning is in fact only toprovide a greater area of bearing between the riser elements 20 of theframe, and the vertical side surfaces of the baffle. Actually, thefunctional portion of the baffle need and does not extend beyond thezone indicated by the line 40 in Fig. 6, or more particularly expressed,th baflle need not be of greater depth than is necessary for thesurfaces characterized .byxthe slopes above..-.described, to reachthevertical. As a general criterion it may benotedlrthjat thedepith.:-of.the functional portion of the zbafile need not exceed thedepth [of the :fan itself. Inuthe case of many prevailing types of threeor fourbladeipropellers, the depth of the fan may be of the order of;2'., while a bafile structure bearing about the space relation to the:fan as shown by Big, ;2,,,:need not exceed a depth, through its;functional :portion, ofone-and one-fourthinc'hes. i

It results from the relatively shallowiform ,of

baflle utilized according to present design, that the baffle can and,preferablyis disposed relatively close to the {an not only-tor thepurpose .of enhancingror ,improvingwthe pattern oi the airstreamudelivered from the :unit, but enabling a further reduction in:overall vertical :dimensional requirements; Some slight spacing of thebaffle beyond theianis desirable but itumayzbe noted that the proximityof baffle and :fan aresuc'hthat no part of the bafile needlbe :spacedfrom the fan a distance greater than two or'three inches. A

.two inch spacing of the ,most 'widelyojseparated portions of bafllendublade, near the peripheries of the fan'and .baille respectively,lhasibeen found entirely adequate in assemblies employingiansof-t-hensual diameters. i

. Assuming a rounded marginal contour such as 34, of'the baflle of'Fig.2, ,it should be'noted that, although a distinctly sectionally curvedprimary bafile surface such as indicated at 4|, is pre Following theforegoing description of structure and design of baffle, no extendeddiscussion of efiectin operation is regarded asnecessary, but it may, benoted for, completeness that the air drawn from below-and into thhousing M by revolution of the fan 23 :is driven'outwardly along thelinesof the arrows of Fig.2, this discharge ,stream from the fanfirstand primarily impinging the surface 4| ;of the baffle. Theaction'of thi annular stream of air upon reaching the rounded cornerportion 34 is of great importance. It is a preference that the sectionalrounding or contouring of the portion 34 be carried through say ninetydegrees of arc ;or' from the :zone indicated at 43 (-Fig. 6) vto the:line indicated at 40, the intermediate half ,of thisangle ofcontouring, being the angle indicated in Fig.-

6, is however {regarded as the more active portion of the convex margin.While the air stream emanating from this zone is of appreciable depth,it will nevertheless proceed with fair uniformity in a generallytangential direction as indicated by arrow 44, the greater part of thetangent stream of air leaving the baffle at point 45. The result of thecontouring, both of the surface 4| and of the margin 34, is that thedischarge stream is characterized by a minimum of turbulence, and byonly a negligible tendency to engage and rebound from the subjacentsupporting surface such as a floor. The stream will norprimary bafiiingsurface at 51, while the convex spaced studs or posts 61.

recess 66.

mally c proceed outwardly and somewhat upwardly, after the manner ofaninverted, relatively fiat parasol;

Although the non-metallic bafile :22 ,of Fig. 2 ofiers certainadvantages, it is distinctly within the purview of the present inventionto cone struct a :baiil say .of pressed metal, and hollow in form.Suchaconstruction isshown by Fig. 3, the contouring .of the active'bafile surface por-' tions of the structure of Fig. 3tbeing in, all:important respects the :same as thatlheretofore described. In thismodification, the center zone of'the baffle is indicated at ,50 and theconvex,

perimetral margin corresponding to :the margin 34 of Fig. 2 is indicatedat '52. For appearance and also. to minimize resonance, a pan likelcoverelement 53 may be provided and secured to :the body :of the b-aiileliAas. by screws :55. The function and several aspects of curvature of thestructure of Fig. .3 may be considered identical with those described inxconnection with baffle 22.

In order toprovide facilities for control of both spread and angulardirection of the annular stream discharged from the unit,.a furthermodification of ballle structure is shown by Figs; 4 and 5. In Fig. 4the baffle structure is characterized by a lower, outwardlyconvex, majoror primary bafflinglelement indicated at 560. "The outer surfaceprovided by the element 66, across the stream of :thefan, is marginallybounded by a convex perimeter 61, the curve characteristics of which areor may be the same as described in respect to the portion 34 of baffle22.; The-:portion 6.1 extends outwardly to form a cylindrical wall ofthe bafile body, indicated at 62, and the baifile is provided with ;atop closure 6'3 secured to the body asbyscrewsifi l.

' In this modification adjustment of slope, and

spread of :the discharge stream :iseifected zby a,

movable secondary baffle in the form of an an;- nulusfit. This elementis preferably formed of a metal stock'of circular section, .and toenclose the ring 65 whencin a-retractedpr non-r-baflling position, thereis provided :an inverted annular This .recess is of a size snugly toaccommodate the ring -65, so that with the latter in its retractedposition it will appear that the element :65 presents a baflling surfacewhich has identical air-deflecting .characteristics with the surface 4!of baffle ,22 and :thesurface 51 of bafile 54., Incases where it :isdesired to confine the spread ,ofthe discharge streamof air .irom theunit 'to a zone relatively close to the .unit, :and :to project thestream somewhat downwardly from its zone of discharge, thesecondarybafilingsuriace constituted by ring 65 may be lowered to the,desired degree :to' bring ,it into the discharge air stream. Facilitiesfor such adjustment consist, :in the example illustrated-in two, or.more, prefer bly ifour, s pporting studs or ,p t

These are lnormallysverticalzas showmand may.

be threaded into or extend through the ring 65 at diametrally spacedpoints. It is a preference to employ four such studs 61, each thereofbeing close and parallel to one of the four riser I elements 20 of theframe whereby to minimize interference of these parts with the outwardlydirected air stream. Arranged diametrally of and within the bafflehousing 62, is one or a pair of cross pieces 10 each apertured near itsopposite ends to receive the upper ends of the diametrally Disposedbelow cross piece or pieces 'HJ are resilient means, suchas a pluralityof compression springs il tending to bias upwardly the cross piece andtherewith, the posts 6? and ring 65, the arrangement tending at alltimes to bring the ring to a retracted or inoperative position.Centrally of one or both of the cross pieces 10, if more than one beemployed, is a socket member 72 provided with a central depression forthe reception of a threaded post 13, the latter being in threadedengagement with a central aperture in a boss 14. The threaded post orstud T3 is provided with a stop member '15 to limit its upward oroutward threaded movement. It will be noted that the threaded element 73extends outwardly through the cover 6 3 of the baflle and is surmountedby a turning knob or the like 16.

It will have appeared that rotation of knob 75 in one direction willoperate to depress, through the socket member, the cross piece or pieces70 and similarly the studs or posts 61 and the ring 65 to bring thelatter into selectively depressed positions in the peripheral portion ofthe outgoing air stream, the deflecting effect of the ring beingillustrated by the section of Fig. 5. When it is desired again toretract and render inactive the secondary baffle surface identified withring 65, the knob 16 is obviously actuated in the opposite direction andthe springs 1|, theretofore compressed, serve to lift the cross piece"H3 and therewith the posts 6'! and ring 65.

It will have appeared that the several structures described serve fullyto attain each of the several objectives hereinabove set forth, andothers implied from the description and function of elements.

For brevity the improvements have been described in connection with arelatively small portable or semi-portable air circulating unit. Thisshould however not be taken as restrictive of application of theprinciples of the invention. It should further be noted that whereverlimits of radii of curvature, or angular extent or spacings arespecified in the description, these limits should be consideredapplicable primarily to unit employing fans of the order of six totwenty inch diameters, without restriction as to units employing largeror smaller size fans.

Many changes in the parts and their described relations are of coursepossible within the intended scope of the claims hereunto appended.

I claim as my invention:

1. In an air circulating assembly, a rotatable air impeller, means foractuating the impeller, a bafrle structure arranged transversely acrossthe impeller discharge stream, the bafile structure including a fixedcentral portion and a peripheral portion movable toward and from theimpeller and in a direction along the impeller axis for varying theangle of discharge of the air by the bafile.

2. In an air circulating assembly, a rotatable air impeller, means foractuating the impeller, a bafile structure arranged substantially acrossthe impeller discharge stream, the baflle structure including a fixedmain baliie portion, an auxiliary baflle portion in the form of anannulus located near the perimeter of the main portion, and means foradjusting the annulusin an axial direction with respect to, and todifferent operating spacings from the impeller.

3. The combination and arrangement of parts as recited by claim 2,further characterized in that the annulus is convex in section and theouter margin of the main baflle portion is also of convex section.

4. In an air circulating assembly, a rotatable air impeller, means foractuating the impeller, a baiiie structure arranged substantially acrossthe impeller discharge stream, the baffle structure including a fixedprimary baille portion characterized by a central area of slightlyconvex sectional contour, and of circular section in planes parallel tothe plane of rotation of the impeller, the primary deflecting surface ofi the baflle terminating peripherally in a convexly rounded margin,which margin thence extends sharply away from the impeller, the bafileincluding an auxiliary baflle ring adjustable into difierent planesgenerally parallel to the plane of rotation of the impeller, the bafiiestructure being hollow and provided with supporting studs for-said ring,projecting from the interior to the exterior thereof into supportingengagement with the ring, a cross piece located diametrally of andwithin the baflie structure and secured to said studs, spring meansbelow the cross piece and tending therethrough to urge the ring to aretracted or inactive position, a screw threaded element operativelyconnected, for adjustment purposes, to the cross piece, and

a member disposed for manual actuation exteriorly of the baflie foradjustment ofsaid ring through said screw threaded means.

, 5. In an air circulating assembly, a rotatable air impeller, a bafflestructure located adjacent the impeller and being characterized by asubstantially uniform convex contour of its major baffling area, and adistinctly convexly rounded margin bounding the major baflling area, thebaiile including an auxiliary bafile ring near the periphery of themajor bailiing area, and adjustable into different planes generallyparallel to the plane of rotation of the impeller, the baffle structurebeing hollow and provided with supporting studs for said ring,projecting from the interior to the exterior of the baille structureinto supporting engagement with the ring, a cross piece locateddiametrally of and within the bafile structure and secured to saidstuds, spring means below the cross piece and tending therethrou'gh tourge the ring to a retracted or inactive position, a screw threadedelement operatively connected, for adjustment purposes, to the crosspiece, and a member disposed for manual actuation exteriorly of thebaffle for adjustment of said ring through said screw threaded means.

EDWARD O. WEHMEYER.

